Ok, so this is a little difficult. I have a brand new singer stylist 7258. Top loading bobber. The bobbin case started to rattle when I went to a higher speed, not much faster by the way. So after long extensive research I found a place that it shows the bobbin wasnt hitting the spring. So I adjusted that. Now the rattling is gone. Ok, great right? NOooo, now every time I start to do a straight stitch the darn thing bird nests underneath. I have cleaned out everything and thread the machine 50 times and now am about to throw it out the window...my needs are good, yes, changed them three times, my string is the same Ive been using, same weight, same type, cotton. My material is also the same, yes there is stabilizer and the right one. Anybody have any clues how to fix this?? I think Ive tried everything and where the machine is only a couple of months old I really dont want to bring to a repair guy already!!!